o
N
N
N
It
is
immaterial which method you use,
in
either case the lens
is
automatically
set to the required distance.
The
Depth
of
Field
Scale
The
sharp definition of the lens
is
not
limited to subjects
at
the exact focused
distance,
but
also covers a certain range
in
front of,
and
behind, this point.
That
zone of sharpness
is
comparatively small
at
full aperture
(f:
2.8), but becomes
greater the more you stop down the lens.
The
depth of field scale (10) shows the
extent of this zone
at
various aperture
settings. Two series of aperture numbers
are engraved for this purpose to the left
and
right of the distance setting index
(11).
The
distance figures on the focusing
scale (12) opposite these aperture num-
bers then indicate the extent of the depth
of ficld. For
in
stance, with the lens set
to
6 feet (Fig. 5), the left-hand figure 8
is
opposite about
41
/2
feet,
and
the right-
hand
figure 8 opposite about 9 feet. Thus
for a subject 6 feet away
and
with the
lens stopped down to
f:
8, everything
between about
41
/2
and
about 9 feet will
be sharp.
The
table on ' page
18
gives
more exact values.
16
To Next Page
Loading...
Need help?
General
